Abstract: The accuracy of life cycle cost (LCC) estimation is crucial to the project investment decisionmaking. The blind number theory is applied to estimate the life cycle cost by presenting a highway construction project as a case study in this paper. Algorithms are presented for the cost estimation for a various of cost items. Results show that, by using the proposed method, high confidence level can be achieved for all the estimation items. The method can be implemented by software, which makes the computation efficient.